| 1. |
- Yazdi, Hossein S., et al.
(författare)
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Mapping breast cancer blood flow index, composition, and metabolism in a human subject using combined diffuse optical spectroscopic imaging and diffuse correlation spectroscopy
- 2017
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Ingår i: Journal of Biomedical Optics. - : SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS. - 1083-3668 .- 1560-2281. ; 22:4
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Tidskriftsartikel (refereegranskat)abstract
- Diffuse optical spectroscopic imaging (DOSI) and diffuse correlation spectroscopy (DCS) are modelbased near-infrared (NIR) methods that measure tissue optical properties (broadband absorption, mu(a), and reduced scattering, mu(s)) and blood flow (blood flow index, BFI), respectively. DOSI-derived mu(a) values are used to determine composition by calculating the tissue concentration of oxy- and deoxyhemoglobin(HbO2,HbR), water, and lipid. We developed and evaluated a combined, coregistered DOSI/ DCS handheld probe for mapping and imaging these parameters. We show that uncertainties of 0.3 mm(-1) (37%) in mu(s) and 0.003 mm(-1) (33%) in mu(a) lead to similar to 53% and 9% errors in BFI, respectively. DOSI/ DCS imaging of a solid tissue-simulating flow phantom and a breast cancer patient reveals well-defined spatial distributions of BFI and composition that clearly delineates both the flow channel and the tumor. BFI reconstructed with DOSI-corrected mu(a) and mu(s) values had a tumor/ normal contrast of 2.7, 50% higher than the contrast using commonly assumed fixed optical properties. In conclusion, spatially coregistered imaging of DOSI and DCS enhances intrinsic tumor contrast and information content. This is particularly important for imaging diseased tissues where there are significant spatial variations in mu(a) and mu(s) as well as potential uncoupling between flow and metabolism. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication,
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| 2. |
- Mohseni, M., et al.
(författare)
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Chiral excitations of magnetic droplet solitons driven by their own inertia
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:2
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Tidskriftsartikel (refereegranskat)abstract
- The inertial effects of magnetic solitons play a crucial role in their dynamics and stability. Yet governing their inertial effects is a challenge for their use in real devices. Here, we show how to control the inertial effects of magnetic droplet solitons. Magnetic droplets are more strongly nonlinear and localized autosolitons than can form in current-driven nanocontacts. Droplets can be considered as dynamical particles with an effective mass. We show that the dynamical droplet bears a second excitation under its own inertia. These excitations comprise a chiral profile, and appear when the droplet resists the force induced by the Oersted field of the current injected into the nanocontact. We reveal the role of the spin torque on the excitation of these chiral modes and we show how to control these modes using the current and the field.
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| 3. |
- Visscher, Peter M., et al.
(författare)
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Genetic survival analysis of age-at-onset of bipolar disorder : evidence for anticipation or cohort effect in families
- 2001
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Ingår i: Psychiatric Genetics. - : Lippincott Williams & Wilkins. - 0955-8829 .- 1473-5873. ; 11:3, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- Age-at-onset (AAO) in a number of extended families ascertained for bipolar disorder was analysed using survival analysis techniques, fitting proportional hazards models to estimate the fixed effects of sex, year of birth, and generation, and a random polygenic genetic effect. Data comprised the AAO (for 171 affecteds) or age when last seen (ALS) for 327 unaffecteds, on 498 individuals in 27 families. ALS was treated as the censored time in the statistical analyses. The majority of individuals classified as affected were diagnosed with bipolar I and II (n = 103) or recurrent major depressive disorder (n = 68). In addition to the significant effects of sex and year of birth, a fitted ‘generation’ effect was highly significant, which could be interpreted as evidence for an anticipation effect. The risk of developing bipolar or unipolar disorder increased twofold with each generation descended from the oldest founder. However, although information from both affected and unaffected individuals was used to estimate the relative risk of subsequent generations, it is possible that the results are biased because of the ‘Penrose effect’. Females had a twofold increased risk in developing depressive disorder relative to males. The risk of developing bipolar or unipolar disorder increased by approximately 4% per year of birth. A polygenic component of variance was estimated, resulting in a ‘heritability’ of AAO of approximately 0.52. In a family showing strong evidence of linkage to chromosome 4p (family 22), the ‘affected haplotype’ increased the relative risk of being affected by a factor of 46. In this family, there was strong evidence of a time trend in the AAO. When either year of birth or generation was fitted in the model, these effects were highly significant, but neither was significant in the presence of the other. For this family, there was no increase in trinucleotide repeats measured by the repeat expansion detection method in affected individuals compared with control subjects. Proportional hazard models appear appropriate to analyse AAO data, and the methodology will be extended to map quantitative trait loci (QTL) for AAO.
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| 4. |
- Mohseni, Seyed Morteza, et al.
(författare)
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Magnetic droplet soliton nucleation in oblique fields
- 2018
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 97:18
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Tidskriftsartikel (refereegranskat)abstract
- We study the auto-oscillating magnetodynamics in orthogonal spin-torque nano-oscillators (STNOs) as a function of the out-of-plane (OOP) magnetic-field angle. In perpendicular fields and at OOP field angles down to approximately 50°, we observe the nucleation of a droplet. However, for field angles below 50°, experiments indicate that the droplet gives way to propagating spin waves, in agreement with our micromagnetic simulations. Theoretical calculations show that the physical mechanism behind these observations is the sign changing of spin-wave nonlinearity (SWN) by angle. In addition, we show that the presence of a strong perpendicular magnetic anisotropy free layer in the system reverses the angular dependence of the SWN and dynamics in STNOs with respect to the known behavior determined for the in-plane magnetic anisotropy free layer. Our results are of fundamental interest in understanding the rich dynamics of nanoscale solitons and spin-wave dynamics in STNOs.
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